Neurovirulência e neuroinvasividade de herpesvírus bovinos tipos 1 e 5 em coelhos

Abstract

This report includes the clinical and pathological studies of a lysosomal storage disease which spontaneously occurred in three flocs of goats e after consumption of Sida carpinifolia, the predominant plant in the paddocks where the animals were grazing. In the outbreaks a total of 25 out of 51 animals were affected. Post-mortem examination was performed on 11 goats. The disease was experimentally induced by dosing goats with Sida carpinifolia. The plant was administered in natura or dried to 3 animals. No clinical or pathological changes were observed in one goat dosed with Sida rhombifolia ad libidum during 40 days. Clinical signs of the poisoning were ataxia, hypermetria, muscle tremors in the head and neck and disorders of deglutition. The clinical signs were exacerbated by movement. After the surviving animals had been moved to other pastures and stopped eating the plant, clinical signs were still observed during 24 months. At necropsy, no significant gross lesions were observed. Microscopic lesions included various degrees of vacuolization in the cytoplasm of neurons and glial cells. Similar lesions were observed in the acinar pancreatic cells, hepatocytes, proximal convoluted tubular cells, follicular epithelial cells of the thyroid gland and macrophages of lymph nodes. In the surviving animals, mild neuronal cytoplasmic vacuolization was observed, and few cells were eosinophilic and shrunken. In these cases neurons, especially Purkinje cells, had disappeared. Through the histochemical study of the cerebellar sections, the lysosomal storage disease was characterized as an alpha-mannosidosis. The vacuoles within the Purkinje cells strongly reacted with lectins of Concanavalia ensiformis, Triticum vulgaris and succinylated Triticum vulgaris. The pattern observed in this investigation is similar to those seen in other poisonings by swainsonine-containing plants.

Distribution of Bovine Herpesvirus Type 5 DNA in the Central Nervous Systems of Latently, Experimentally Infected Calves

“…We and others (3,25,35; Vogel et al, submitted) have already noticed that BHV-5 may be excreted for longer periods than BHV-1 upon experimental inoculation. Whether these findings were circumstantial (derived from different experimental conditions, animal age and genetic background, and/or different virus strains) or whether they reflect an inherent property of BHV-5 that distinguishes it from BHV-1 is still unclear.…”

Neurological disorder in cattle associated with bovine herpesvirus 4

“…In samples which failed to amplify this gene, the DNA extraction and PCR were repeated. Positive control for each PCR was included in every test, which consisted of purified DNA as follows: BHV-5, strain EVI-88 (Spilki et al, 2002); SHV-1, strain A031 (Flatschart and Resende, 2001); OHV-2, strain F1 (Andrade et al, 2006). In all field samples internal control (IGF-1) gene was used.…”

Neuropatogênese experimental da infecção pelo herpesvírus bovino tipo 5 em coelhos

“…Localizado o espaço subaracnóide, procede-se a inoculação do vírus com auxílio de uma agulha calibre 22G. A suspensão viral deve ser aquecida a 37°C e administrada lentamente (Laskin & Griffin 1987, Spilki et al 2002. Cuidados especiais devem ser tomados quanto à profundidade da inserção da agulha, sendo o local adequado facilmente determinado pela sensação do rompimento da dura-máter e o extravasamento de líquor através da agulha, que deve ser inserida inicialmente desacoplada da seringa.…”

“…Histologicamente, observa-se meningoencefalite não supura- tiva, de intensidade variável e geralmente correlacionada com a duração e severidade do curso clínico (Chowdhury et al 1997, Silva et al 1999b. Os achados mais freqüen-tes são gliose focal ou difusa e infiltrado perivascular mononuclear (Silva et al 1999b, Caron et al 2002, Spilki et al 2002. Pequenas hemorragias focais ou multifocais e congestão das meninges também são achados freqüen-tes (Caron et al 2002).…”

“…Assim, a capacidade de produzir doença neurológica em coelhos pode ser utilizada como um parâmetro a mais na diferenciação entre BoHV-1 e BoHV-5. A exceção se faz a uma única cepa de BoHV-1, a cepa padrão Los Angeles, que induziu doença com sinais neurológi-cos em coelhos, após inoculação pela via IN (Spilki et al 2002). A mesma cepa não produz doença neurológica em bovinos, mas características antigênicas e genômicas (Engels et al 1985) demonstram diferenças entre esta cepa e outras amostras de BoHV-1.…”